Volumetric parameters from [18 F]FDG PET/CT predicts survival in patients with high-grade gastroenteropancreatic neuroendocrine neoplasms.

A positive fluorine-18 labelled 2-deoxy-2-fluoroglucose ([18 F]FDG) positron emission tomography/computed tomography (PET/CT) has been associated with more aggressive disease and less differentiated neuroendocrine neoplasms (NEN). Although a high maximum standardized uptake value (SUVmax ) predicts poor outcome in NEN, volumetric parameters from [18 F]FDG PET have not been evaluated for prognostication in a pure high-grade gastroenteropancreatic (GEP) NEN cohort. In this retrospective observational study, we evaluated the volumetric PET parameters total metabolic tumour volume (tMTV) and total total lesion glycolysis (tTLG) for independent prognostication of overall survival (OS). High-grade GEP NEN patients with [18 F]FDG PET/CT examination and biopsy within 90 days were included. Total MTV and tTLG were calculated using an adaptive thresholding software. Patients were dichotomised into low and high metabolic groups based on median tMTV and tTLG. OS was compared using Kaplan-Meier estimator and log-rank test. Uni and multivariable Cox regression was used to estimate effect sizes and adjust for tumour differentiation and SUVmax . Sixty-six patients (median age 64 years) were included with 14 NET G3 and 52 NEC cases after histological re-evaluation. Median tMTV was 208 cm3 and median tTLG 1899 g. Median OS in the low versus high tMTV-group was 21.2 versus 5.7 months (HR 2.53, p = 0.0007) and 22.8 versus 5.7 months (HR 2.42, p = 0.0012) in the tTLG-group. Adjusted for tumour differentiation and SUVmax , tMTV and tTLG still predicted for poor OS, and both tMTV and tTLG were stronger prognostic parameters than SUVmax . Both regression models showed a strong association between volumetric parameters and OS for both neuroendocrine tumours (NET) G3 and neuroendocrine carcinomas (NEC). OS for the tTLG low metabolic NEC was much higher than for the tTLG high metabolic NET G3 (18.3 vs. 5.7 months). High-grade GEP NEN patients with high tMTV or tTLG had a worse OS regardless of tumour differentiation (NET G3 or NEC). Volumetric PET parameters were stronger prognostic parameters than SUVmax .

Prognostic significance of conventional and volumetric PET parameters with and without partial volume correction in the assessment of head and neck squamous cell carcinoma.

BACKGROUND: The optimal quantification of PET in assessment of head and neck squamous cell carcinoma (HNSCC) is still under development. The effect of partial volume correction (PVC) on the evaluation of survival in the HNSCC patients has not been investigated yet. METHODOLOGY: Pretreatment 18F-FDG-PET/CT scans of a selected group of 57 patients with advanced stage HNSCC were collected. Conventional (SUVmean and SUVmax) and volumetric [total lesion glycolysis (TLG) and metabolic tumor volume (MTV)] PET metrics were calculated. The ROVER software (ABX GmbH, Radeberg, Germany) automatically applied PVC to the PET metrics. Cox proportional hazards regression model calculated hazard ratio (HR) for assessment of predictive parameters of progression-free survival (PFS). RESULTS: In multivariate Cox regression analysis, including age, gender, race, human papillomavirus status, and stage, the only significant predictors of PFS were the volumetric PET parameters (TLG: HR, 1.003; 95% CI, 1.001-1.005; P = 0.02), pvcTLG (HR, 1.002; 95% CI, 1.001-1.004; P = 0.01) and MTV (HR, 1.050; 95% CI, 1.024-1.077; P < 0.01). The partial volume-corrected values were significantly higher than the noncorrected values (Wilcoxon sign test; P < 0.05). However, there was not a statistically significant difference between the nonpartial volume corrected and partial volume-corrected PET metrics for assessment of PFS. CONCLUSION: Volumetric PET metrics were predictors of PFS in Cox regression analysis. Applying PVC could not significantly improve the accuracy of PET metrics for assessment of PFS.

Assessment of atherosclerosis in multiple myeloma and smoldering myeloma patients using 18F- sodium fluoride PET/CT.

BACKGROUND: To compare the NaF uptake in the thoracic aorta and whole heart, as an early indicator of atherosclerosis, in multiple myeloma (MM) and smoldering multiple myeloma (SMM) patients with a healthy control (HC) group. METHODS: Forty-four untreated myeloma patients (35 MM and nine SMM) and twenty-six age and gender-matched HC subjects were collected. Each individual's NaF uptake in three parts of the aorta (AA: ascending aorta, AR: aortic arch, DA: descending aorta) and the whole heart was segmented. Average global standardized uptake value means were derived by sum of the product of each slice area divided by the sum of those slice areas. Results were reported as target to background ratio (TBR). RESULTS: There was a significant difference between the NaF uptake in the thoracic aorta of myeloma and HC groups [AA (myeloma = 1.82 ± 0.21, HC = 1.24 ± 0.02), AR (myeloma = 1.71 ± 0.19, HC = 1.28 ± 0.03) and DA (myeloma = 1.96 ± 0.28, HC = 1.38 ± 0.03); P-values < 0.001]. The difference in the whole heart NaF uptake between two groups was also significant (P < 0.001). CONCLUSIONS: We observed a higher uptake of NaF in the thoracic aorta and whole heart of myeloma patients in comparison to the matched control group.

Correlation of whole-bone marrow dual-time-point 18F-FDG, as measured by a CT-based method of PET/CT quantification, with response to treatment in newly diagnosed multiple myeloma patients.

The practical application of dual-time-point-imaging (DTPI) technique still remains controversial. One of the issues is that current parameters of DTPI quantification suffer from some deficiencies, mainly limited sampling of the diseased sites by confining measurements to specific locations. We aimed to examine the correlation between the percent change from early to delayed scans in whole-bone marrow (WBM) 18F-FDG uptake, as measured by a CT-based method of PET/CT quantification, and response to treatment in multiple myeloma (MM) patients. Pre-treatment 18F-FDG-PET/CT scans of 36 newly diagnosed MM patients were collected in a prospective study at 1 h and 3 h post tracer injection (NCT02187731). A threshold algorithm based on bone Hounsfield units on CT was applied to segment and quantify WBM 18F-FDG uptake. Patients were separated into two treatment groups: high-dose therapy with autologous stem cell transplant (HDT) and non-high dose therapy (non-HDT). The International Response Criteria for MM patients was used to determine each patient's response to treatment. In the HDT group, WBM 18F-FDG uptake increased significantly in patients that had a poor response to treatment, from a median of 1.31 (IQR: 1.13-1.64) at 1 h to a median of 1.85 (1.45-2.10) at 3 h. The median percent change was 37.77% (IQR: 23.47-46.4), with a range of 6.10-50.73 (P = 0.003). However, no significant change in uptake was observed in patients with a complete response (P = 0.24). The same trend was observed for the non-HDT group. WBM uptake of 18F-FDG assessed with dual-time-point imaging may have a role in predicting treatment response in MM.

Role of FDG-PET/CT in Assessing the Correlation Between Blood Pressure and Myocardial Metabolic Uptake.

OBJECTIVES: We aimed to assess the association between blood pressure and LV myocardial uptake of FDG, hypothesizing that subjects with raised blood pressure would have higher FDG uptake. METHODS: We analyzed 86 healthy controls who underwent PET/CT imaging 180 minutes following FDG (4 MBq/Kg) administration. LV myocardial analysis was performed on axial sections using standard operator guided computer software (OsiriX MD). The average LV myocardial SUVmean (MSUVmean) was calculated for each subject. Subjects were assessed according to the 2017 ACC/AHA guidelines for high blood pressure in adults. Mean arterial blood pressure (MABP) was calculated for each patient. Regression models were employed for statistical analysis. RESULTS: The association of MSUVmean was more pronounced with DP (r=0.32, p=0.003) than SP (r=0.28, p=0.010); MABP was comparable (r=0.33, p=0.002). Correlations of MSUVmean with categorized BPs were: normal SP (r=0.27, p=0.010), elevated SP (r=0.28, p=0.009), stage 1 SP (r=0.27, p=0.010), stage 2 SP (r=0.28, p=0.008); normal DP (r=0.33, p=0.001), stage 1 DP (r=0.34, p=0.001), stage 2 DP (r=0.35, p=0.001). Multivariate analysis demonstrated DP (p=0.006), MABP (p=0.007), and SP (0.026). CONCLUSION: LV myocardial FDG uptake was higher in subjects with elevated blood pressure and correlated positively with SBP and in particular DBP and MABP.

A Pilot Study of FDG-PET/CT in Polycythemia Vera Using Global Analysis Techniques.

OBJECTIVES: Functional imaging presents a non-invasive process that may capture the hyper-metabolic nature of red bone marrow in myeloproliferative neoplasms, such as polycythemia vera (PV). METHODS: This study analyzed the FDG-PET/CT scans (n=12) of six patients diagnosed with PV and six age-sex matched controls using a quantitative global analysis methodology. RESULTS: All PV patients had elevated activities in the bone marrow of each skeletal structure as compared to matched controls with respect to mean standardized uptake value (femoral neck p=0.01, lumbar spine p=0.02, pelvis p=0.002, sternum p=0.04). Notable variations in splenic uptake were observed among the treated and untreated PV patients. CONCLUSION: Our study exemplifies the potential utility of PET in reflecting hyperactive bone marrow activity related to PV. Future studies may further substantiate and elaborate on the use of PET-derived metabolic data in PV.

Assessment of Physiological Intracranial Calcification in Healthy Adults Using 18F-NaF PET/CT.

The aim of this research study was to determine the role of 18F-Sodium fluoride (NaF) PET/CT imaging in the assessment of physiologic molecular calcification in the intra-cranial structures. We also examined the association of NaF accumulation with age as well as Hounsfield unit (HU) in certain anatomical sites that are known to calcify with normal aging. Methods: A total of 78 healthy subjects from the Cardiovascular Molecular Calcification Assessed by 18F-NaF PET/CT (CAMONA) clinical trial (38 females and 40 males) were included in this retrospective study. The mean age was 45.28 ±14.15 years (21-75). Mean standardized uptake values (SUVmean) was used to measure NaF accumulation in the choroid plexus and epithalamus (pineal gland and habenula). Maximum HU was also measured for each ROI. Correlation analysis was conducted to assess the association between parameters. Results: Mean SUVmean was 0.42 ± 0.26 in the right choroid plexus, 0.39 ±25 in the left choroid plexus, and 0.23±0.08 in the epithalamus. Significant positive correlations were present between NaF uptake and age in the right choroid plexus (r=0.61, P < 0.0001), left choroid plexus (r=0.63, p<0.0001), and epithalamus (r=0.36, P = 0.001). NaF uptake significantly correlated with HU in the right choroid plexus (r=0.52, P < 0.0001), left choroid plexus (r=0.57, p<0.0001), and epithalamus (r=0.25, P = 0.03). Conclusion: NaF could be used in the assessment of physiological calcification in several intracranial structures. We report significant associations between NaF uptake and aging as well as HU in the calcified choroid plexus and epithalamus. Our findings further support the growing interest to utilize NaF for detecting extra-osseous, molecular calcification, and this powerful probe has potential applications in the evaluation of various age-related, neurodegenerative brain processes.